Tools such as knives having a handle and a blade are often carried in sheaths attached to an article of clothing of the user. Certain prior art sheaths undesirably allow the knife to often become dislodged from the sheath when the user is active or when the sheath is not in an upright position. Various methods to prevent the knife from falling out of the sheath, or otherwise becoming dislodged, are well known in the art. U.S. Pat. No. 3,958,330, issued May 25, 1976 to Hutchens discloses a knife and sheath combination wherein the knife and sheath are provided with mating areas to prevent the accidental release of the knife from the sheath.
Other more complex mechanisms have also been used to alleviate this problem. In particular, U.S. Pat. No. 4,827,614, issued May 9, 1989 to Mitchell discloses a double safety lock and quick release tool and sheath assembly in which the locking mechanism includes a pair of spring-biased pins secured to the handle of the tool. The two locking pins protrude above the surface of the tool handle and tightly fit within two corresponding apertures of the tool holder. The locking mechanism also includes two activators which permit the user to release the tool from the tool holder. Similarly, U.S. Pat. No. 5,123,167, issued June 23, 1992 to Kelley is directed to a knife in which the handle is provided with an integral latch member displaceable by the fingers of the user. The latch engages a corresponding aperture formed in the knife sheath.
From the foregoing, it is readily apparent that these prior art inventions suffer from a number of shortcomings. In particular, and most importantly, all such prior art items do not permit adjustment of the retaining force of the knife within the sheath In addition, in some of these items, numerous parts and complex assemblies are required to establish this retentional feature Finally, and as illustrated by Kelley, recent attempts to find simpler ways to provide the desirable interlocking of the knife with the sheath have resulted in the knife itself comprising an exposed, cumbersome, fragile, locking mechanism which may impede operation of the knife by the user, and which may be damaged during normal use of the knife.
Thus, it is highly desirable to provide a sheath which can alleviate the problems associated with conventional interlocking knife/sheath combinations, i.e., which permits adjustment of the force retaining the knife within the sheath, which is of simple construction yet durable, and which does not impede operation of the knife by the user.